“On Approximation of Signals in Lip(α,r)-Class Using the Product (N, pn,qn)(E,s)- Summability Means of Conjugate Fourier Series: On Approximation of Signals in $Lip(\alpha,r)$-class. ”. Nonlinear Studies, vol. 27, no. 2, May 2020, https://www.nonlinearstudies.com/index.php/nonlinear/article/view/1575.